Filter-out legacy filenames that are not UTF-8 encodable.

Emacs's json serialization only supports UTF-8.
Since sonarlint requires emacs to provide the whole list of files
in the workspace, this can be an issue when filenames use
ISO 8859 accentuated characters typically.

The simplest work around seems to filter-out those files,
but I guess sonarlint won't work on those.

Author: Horrih

lsp-sonarlint.el

@@ -286,20 +286,30 @@ temporary buffer."
 i.e folders starting with '.' will be ignored"
   (not (string= (substring (file-name-base dirname) 0 1) ".")))
 
+(defun lsp-sonarlint--invalid-file-name-encoding(file-path)
+  "Return t if the file-path is not encodable as UTF-8.
+This is important since emacs does not support non UTF-8 json serialization,
+so a stray accentuated character encoded in a legacy filename in 8859-1
+will raise an error for the whole project."
+  (cl-some (lambda (ch)
+             (not (encode-coding-char ch 'utf-8 'unicode)))
+           file-path))
+
 (defun lsp-sonarlint--list-files-in-folder (workspace _params)
   "Respond to a listFilesInFolder request.
 List all files of interest in WORKSPACE's directory.
 See `lsp-sonarlint-analyze-folder' to see which files are ignored."
   (let* ((root-dir (lsp--workspace-root workspace))
-         (files (directory-files-recursively root-dir ".*" nil 'lsp-sonarlint--analyze-folder)))
+         (files (directory-files-recursively root-dir ".*" nil 'lsp-sonarlint--analyze-folder))
+         (utf8-filenames (cl-remove-if #'lsp-sonarlint--invalid-file-name-encoding files)))
     (lsp-ht
      ("foundFiles"
-       (apply 'vector
-              (mapcar (lambda(file)
-                        (lsp-ht
-                         ("fileName" (file-name-nondirectory file))
-                         ("filePath" file)))
-                      files))))))
+      (apply 'vector
+             (mapcar (lambda(file)
+                       (lsp-ht
+                        ("fileName" (file-name-nondirectory file))
+                        ("filePath" file)))
+                     utf8-filenames))))))
 
 (defvar lsp-sonarlint--action-handlers '())